In a conventional organic electroluminescence (hereinafter, referred to as organic EL) illumination device, as shown in FIGS. 39 and 40, anode terminal electrodes 11 are formed respectively on four sides of a glass substrate 10 and cathode terminal electrodes 12 are formed respectively on four corners of the glass substrate 10 to make an organic EL illumination panel with a large area uniformly emit light. Moreover, entire surfaces of the anode terminal electrodes 11 and the cathode terminal electrodes 12 are covered with a solder (hereinafter, referred to as underlying solder) to reduce a wiring resistance.
Further, a current is evenly supplied to an organic EL element 13 from four directions through the anode terminal electrodes 11 and the cathode terminal electrodes 12.
In addition, a sealing can 14 for preventing performance deterioration of the organic EL element 13 due to oxygen, water, and the like is formed on the glass substrate 10 to cover the organic EL element 13.
Moreover, as shown in FIG. 41, the anode terminal electrodes 11 are connected to one another with anode lead wires 20 and the cathode terminal electrodes 12 are connected to one another with cathode lead wires 21 by using a soldering method.
Further, as shown in FIG. 42, an anode lead-out wire 22 is connected to one of the anode terminal electrodes 11 and a cathode lead-out wire 23 is connected to one of the cathode terminal electrodes 12. A connector 24 is attached to end portions of the anode lead-out wire 22 and the cathode lead-out wire 23. The current is supplied to the organic EL element 13 from the connector 24.
Patent Document 1 listed below discloses an organic EL illumination device with the following characteristics as an example of the conventional organic EL illumination device. In an organic EL element including at least a transparent anode layer, an organic light-emitting medium layer, and a cathode layer, an auxiliary electrode layer is provided which is stacked on the cathode layer with an insulating layer in between and which is in contact with the transparent anode layer.
Moreover, Patent Document 2 discloses an organic EL illumination device with the following characteristics as an example of the conventional organic EL illumination device. An insulating protective film which protects an organic EL element from oxygen and water is formed. A conductive film covering an upper electrode with the protective film securing insulation between the conductive film and the upper electrode has one portion connected to a connection terminal of a lower electrode or an end portion of the lower electrode on a side closer to the connection terminal and has another portion connected to an end portion of the lower electrode on an opposite side from the connection terminal. The conductive film is formed of a metal film and is formed on an insulating film.
In Patent Documents 1 and 2, an auxiliary electrode which reduces a wiring resistance is formed only on one side of the transparent electrode made of indium tin oxide (hereinafter, referred to as ITO) or the like with high resistance.